Phonographic recording apparatus.



'T.'A. EDISON. PHONOGHAPHIC RECORDENG APPARATUS.

APPLICATIQN FILED JAN-27.1910.

L 15%,fl 1 I Patented Sept. 7, 1915.

2 SHEETS-SHEET l.

I T. A. EDESON. PHON'OGRAPHIC RECORDING APPARATUS.

APPLICATION EILED JAN 21' 1910.

1,152,614; I v PatentedSe-pt. 7,1915.

2 SHEETS-SHEET 2.

THOMAS A. EDISON, 0F LLEWELLYN PARK, WEST ORANGE, NEW JERSEY, ASSIGNOR TO NEW JERSEY PATENT COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PHONOGRAPHIC RECORDING APPARATUS.

Specification of Letters Patent.

rammed Sept. 7,1915.

Applicationfiled January 27, 1910. Serial No. 540,317.

To all whom it may concern:

Be it known that I, THOMAS A. En1soN,

a citizen of the United States, and aresi dent of Llewellyn Park, West Orange, county of Essex, and State of New Jersey, have made a certain new and useful Invention in Phonographic Recording Apparatus, of which the following is a description.

My invention relates to phonographic re cording apparatus, and my object is to provide a recording apparatus which is extremely sensitive to vibrations of small amplitude, but which is relatively insensitive to vibrations of large amplitude. Heretofore, recording devices which have been sufficiently sensitive to record vibrations of small amplitude, have permitted the diaphragm to move excessively-when recording vibrations of relatively great amplitude. On

the other hand, diaphragms which are sufficiently stiff and sensitive to permit practicable recording of vibrations of great am.-

plitude have been practically unresponsiveto the very small vibrations which often give' character andquality to music.

As it is necessary to keep the maximum movement of the diaphragm within certain limits, my invention provides an extremely sen tive diaphragm, preferably of cork, which shall be readily responsive even to excessivelyweak vibrations, and I employ in cooperation therewith a braking or re-- tardin'g device having the peculiarity of imposing resistance to the diaphragm only when ititends to vibrate to an undue extent, so as to thereby dampen and control its movements under the effect of sound vibrations of great amplitude. The advantages of a cork diaphragm are-pointed outinmy application Serial No. 526,036, filed Nov. .3, 1909. The braking or retarding means referred to are positioned preferably on the side of the diaphragm distant from the stylus. I will describe herein two suggested arrangements, either of which is adapted to perform tln function described.

In order that the invention may be better understood, attention is hereby directed to the accompanying drawin s, forming part of this specification, and in which I illustrate two forms of apparatus embodying my invention.

Figure lirepresents a vertical cross sectional view of one form of apparatus embodying my'invention. Fig. 2 represents a bottom plan view thereof. Fig. 3 represents a vertical cross'sectional view of a second form of apparatus embodying my inven-- tion, and Fig. lrepresents a bottom plan view thereof.

Referring to the drawings, the diaphragm 1 of cork or other desired material is secured in any desired manner to the sound box 2 The recording stylus 3 is carried by the arm ll which may besecured to the flange of sound box 2, as shown in the drawings, or otherwise suitably mounted, the foot 5 integral with or secured to arm 4 being cemented or 'otherwise secured to the center of the underside of the diaphragm as indicated at 6.

- Referring to the form of my apparatus shown in Figs. 1 and 2, a small cylinder 7 is secured axially to the upper side of the diaphragm 1 and the plunger 8 is positioned within the cylinder. This plunger is secured to the sound box 2 in any desired manner, so that the air confined within the cylinder below the plunger is compressed by upward movement of the diaphragm to prevent excessive movement of the latter. As shown in the drawings, the plunger is provided with an upper portion 9 of reduced diameter, which is connected by aball and socket joint 10 with an adjusting screw 11, which is threaded within the wall of sound box 2, as shown. By making use of a ball and socket joint as described, the danger of the plunger cramping within the cylinder v7 is overcome, andasmooth relative movement-of the two elements is permitted at all times. The

portion of the Wall of sound box 2 in which screw 11 1s threaded, may itself be removably secured, as by a screw engagement within a threaded opening in the wall of the sound box, as shown in the drawings, for.

plunger 8 might be reversed, the plunger being secured to the diaphragm, and the cylinder to'the sound box.

Referring. tothe formr'ofjmy invention shownin Figs. 3 and hthe'screw 11 is tween the diaphragm andthe lower surface of head This sticky material is too-viscons to How" to any extent, and acts prac tically in the same manner as the air cushion described in connection with'Figs. l and'2. In either case the compression of the air 'or the distortion of the viscous material imposes substantially no resistance to move-.

ments' of the diaphragm caused'by very weak vibratlons, whereas, in the case of sound vibrations otgreat magnitude, the

v movements of thediaphragm are dampened and kept within practicable limits.

Both forms of cushioning means herein disclosed are substantially incapable of being set into continued vibration by the ela'sticity thereof and therefore offer no ob-;

jectionable interference to the true vibration of the diaphragm.

It is to be understood that I am not limited to the exact details of construction shown in the drawings, but that my invention is as broad as'the appended claims.

Having now described myinvention, what I claim and desire to-protectby Letters Patent is as follows: 3-

.1. In a device of the class described, the combination of a sound box, a diaphragm mounted therein, a stylus in operative relation to said diaphragm, and means bearing on said diaphragm and comprising an air chamber for imposing a resistance to the vibrations of the diaphragm, substantially as described. I Y

2. Ina device of theclass described, the combination of a sound box,- a diaphragm mounted therein, a stylus in operative relation to said diaphragm, and means for imposing resistance to the vibrations of the Copies of this patent may be obtained for diaphragm, comprising an air chamber and a plunger fitting therein, one of said parts bearing on said diaphragm, said air chamber and plunger being manually adjustable v relatively to each other for varying the resistance to the movement'of the diaphragm, substantially as described.

3. In phonographic sound recording apparatus, in combination, a sound box, a diaphragm secured thereto, a stylus connected therewith, and a device for imposing a resistance to the vibrations of the diaphragm of considerable amplitude, comprising a cylinder and a plunger closely fitting therein, said parts being relatively movable, and one of said parts bearing on and moving with said diaphragm, substantially as described.

4-. In phonographic sound recording apparatus, in combination, a sound box, a diaphragm secured thereto, a stylus connected therewitlnfa cylinder and aplunger closely fitting therein, one of said parts being secured to' said diaphragm and the other of said parts being secured to said sound box, and supporting means for one of said parts constructed to'prevent binding between said cylinder and plunger in their relative movement, substantially as described.

5. In phonographic sound recording apparatus, in combination, a sound box, a diaphragm secured thereto, a stylus connected therewith, a cylinder secured axially to said diaphragm, a plunger fitting closely therein, an adjustable member secured in said-sound box axially in line with said plunger, and a ball and socket connection between said member and said described.

6. In phonographic sound recording apparatus, in combination, a sound box, a diaphragm secured thereto, a stylus connected with said diaphragm, means for imposing a resistance to the vibration of the diaphragm plunger, substantially as p comprising a cylinder and a plunger closely fitting therein, and means for manually adjusting the normal positions of said cylinder and plunger axially of each other, substantially as described.

This specification signed and witnessed this 26th day of January 1910. THOS. A. EDISON.

' Witnesses: DYER SMITH,

JOHN M. CANFIELD.

five cents each, by addressing the Opmmissionerot Patents, Washington, D. 0. 

